Noise Reduction of Condenser Cooling Fans for Automotive Air Conditioners

The axial fan used for a pusher-type condenser cooling system of automotive air conditioners is one of the major sources of noise in an engine room, and many efforts have been made to reduce the noise emitted from the fan. In this paper, mechanism of the noise generation by a fan in the pusher-type cooling system is clarified, and some methods are presented to decrease the turbulent noise from it. Detailed studies on the flow around the fan were carried out both by computer simulations and LDA (Laser Doppler Anemometer) measurements. A considerable reduction in the noise level of the pusher-type cooling system has been achieved without any deterioration in the performance for different resistances in the condenser cooling system.